Positive Affect and Incidence of Frailty in Elderly Women Caregivers and Noncaregivers: Results of Caregiver–Study of Osteoporotic Fractures

OBJECTIVES: To determine whether positive affect is associated with a lower incidence of frailty over 2 years in elderly community-dwelling women and to test the stress-buffering hypothesis by evaluating whether these associations differed in caregivers and noncaregivers.
DESIGN: Prospective cohort study with three annual interviews conducted in four U.S. communities between 1999 and 2004.
SETTING: Home-based interviews.
PARTICIPANTS: Three hundred thirty-seven caregiver and 617 noncaregiver participants from the Caregiver-Study of Osteoporotic Fractures (Caregiver-SOF) who were not frail at the baseline Caregiver-SOF interview.
MEASUREMENTS: High and low positive affect and depressive symptoms were derived from the baseline 20-item Center for Epidemiologic Studies Depression Scale. Frailty was the development of three or more indicators (weight loss, exhaustion, slow walking speed, or weak grip strength) at the first or second follow-up interview.
RESULTS: Respondents' mean age was 81.2. Caregivers and noncaregivers had similar levels of positive affect (56.3% vs 58.3%) and frailty incidence (15.4% vs 15.9%) but differed in perceived stress (mean Perceived Stress Scale score 16.7 vs 14.8, P <.001). Frailty risk was lower in respondents with high positive affect than in those with low positive affect in the total sample (adjusted hazard ratio (HR)=0.49, 95% confidence interval (CI)=0.35–0.70), caregivers (adjusted HR=0.44, 95% CI=0.24–0.80) and noncaregivers (adjusted HR=0.50, 95% CI=0.32–0.77).
CONCLUSION: These findings add to the evidence that positive affect protects against health decline in older adults, although it had no additional stress-buffering effect on health in elderly caregivers.     

Pearling in cells: A clue to understanding cell shape

Gradual disruption of the actin cytoskeleton induces a series of structural shape changes in cells leading to a transformation of cylindrical cell extensions into a periodic chain of "pearls." Quantitative measurements of the pearling instability give a square-root behavior for the wavelength as a function of drug concentration. We present a theory that explains these observations in terms of the interplay between rigidity of the submembranous actin shell and tension that is induced by boundary conditions set by adhesion points. The theory allows estimation of the rigidity and thickness of this supporting shell. The same theoretical considerations explain the shape of nonadherent edges in the general case of untreated cells.     

Zika RNA and Flavivirus-Like Antigens in the Sperm Cells of Symptomatic and Asymptomatic Subjects

Zika virus (ZIKV) RNA has been found to remain in human semen for up to one year after infection, but the presence of Flavivirus antigens in the different compartments of semen has been largely unexplored. Following the introduction of ZIKV in Nicaragua (2016), a prospective study of patients with clinical symptoms consistent with ZIKV was conducted in León to investigate virus shedding in different fluids. ZIKV infection was confirmed in 16 male subjects (≥18 years of age) by RT-qPCR in either blood, saliva or urine. Of these, three provided semen samples at 7, 14, 21, 28, 60 and 180 days postsymptom onset (DPSO) for Flavivirus antigens and RNA studies. These cases were compared with 19 asymptomatic controls. Flavivirus antigens were examined by immunofluorescence (IF) using the 4G2 Mabs, and confocal microscopy was used to explore fluorescence patterns. The three (100%) symptomatic subjects and 3 (16%) of the 19 asymptomatic subjects had Flavivirus antigens and viral RNA in the spermatozoa fraction. The percentage of IF Flavivirus-positive spermatozoa cells ranged from 1.9% to 25% in specimens from symptomatic subjects, as compared with 0.8% to 3.8% in specimens from asymptomatic controls. A marked IF-pattern in the cytoplasmic droplets and tail of the spermatozoa was observed. The sperm concentrations (45 × 10⁶/mL vs. 63.5 × 10⁶/mL, p = 0.041) and the total motility percentage (54% vs. 75%, p = 0.009) were significantly lower in specimens from ZIKV-positive than in those of ZIKV-negative. In conclusion, this study demonstrated the presence of Flavivirus antigens and RNA within a time frame of 28 DPSO in sperm cells of symptomatic and asymptomatic subjects during the ZIKV epidemic. These findings have implications for public health, in terms of nonarthropod-born, silent transmission facilitated by sperm cells and potential transmission from asymptomatic males to pregnant women, with consequences to the fetus.     

Elderly patients with hip fracture with positive affect have better functional recovery over 2 years

OBJECTIVES: To evaluate whether patients with hip fracture with high positive affect had better functioning than those with low positive affect or depressive symptoms in three performance-based measures over 2 years after the fracture. DESIGN: Longitudinal study with assessments at baseline and 2, 6, 12, 18, and 24 months posthospitalization. SETTING: Community. PARTICIPANTS: Four hundred thirty-two patients, aged 65 and older, hospitalized for hip fracture in Baltimore, Maryland, between 1990 and 1991. MEASUREMENTS: High and low positive affect and depressive symptoms were based on baseline Center for Epidemiologic Studies Depression Scale score, usual and rapid walking speed, one chair stand, demographic factors, comorbidities, and history of cognitive impairment. RESULTS: At each follow-up point, respondents with high positive affect at baseline (36% of sample) had faster walking and chair stand speeds than those with low positive affect (13%) and depressive symptoms (51%). For example, at 6 months, the mean usual walking pace was 0.4 m/s (standard error (SE)=0.02) for respondents with high positive affect, versus 0.4 m/s (SE=0.03) and 0.35 m/s (SE=0.02) for patients with low positive affect and depressive symptoms, respectively; adjusted differences were 0.02 (95% confidence interval (CI)=-0.06-0.09) and 0.06 (95% CI=0.01-0.11). Respondents with high positive affect appeared to achieve their maximum improvement in usual pace approximately 6 months before other respondents, but this interaction was not statistically significant. Respondents with consistently high positive affect had the best functioning over the follow-up period. CONCLUSION: High positive affect seems to have a beneficial influence on performance-based functioning after hip fracture.     

Altered expression of ganglioside phenotypes of human gliomas in vivo and in vitro

A library of epitope-defined antiganglioside monoclonal antibodies has been used to analyze the ganglioside phenotype of human glioma cell lines, rodent xenografts derived from them, and a separate panel of human glioma biopsies by multiple quantitative and qualitative assays. We have shown that the ganglioside phenotypes of cultured cell lines differ from the ganglioside phenotypes in the xenografts grown from the parent lines. The lacto series gangliosides 3′-isoLM1 and 3′, 6′-isoLD1 are expressed in the majority of primary human central nervous system neoplasms and xenografts derived from glioma cell lines, whereas glioma cell lines themselves express 3′-isoLM1 and 3′, 6′-isoLD1 in only 2/15 and 0/15 cases, respectively. Examination of the ganglioside profiles of serially passaged xenografts established from the glioma cell line D-54 MG, which does not express the lacto series, revealed the appearance of these gangliosides within one to two passages in vivo. The presence of these defined gangliosides in the majority of human gliomas and their absence in normal brain supports their application in compartmental therapy of primary central nervous sytem tumors.     

THE PRESENCE OF ENDOGENOUS PYROGEN IN NORMAL RABBIT TISSUES

Saline extracts of homogenized, uninfected, rabbit tissues produced febrile responses when injected intravenously into rabbits. Extracts of muscle, lung, and heart evoked fevers that were similar to those induced by leucocyte pyrogen; extracts of spleen, liver, and kidney caused more sustained fevers. The minimal pyrogenic dose appeared to be between 1.5 and 3 gm wet weight of tissue. Evidence is presented that neither Gram-negative bacterial endotoxin nor polymorphonuclear leucocytes (circulating or sequestered in the tissues) can be implicated as the source of pyrogen in tissue extracts. It seems likely, therefore, that a pyrogenic material of truly endogenous origin is widely distributed in tissues. Tissue pyrogen appears to be a large molecule which is relatively resistant to treatment with acid but not with alkali. Possible pathological roles for this endogenous agent (or agents) are briefly indicated.     

Does the combination of a simultaneous subcapital fracture of humerus and hip fracture in elderly patients carry a prognostic value?

The most important factor to cause hip fractures in elderly is probably osteoporosis. Other factors are the increase in fall frequency and the protective response to trauma. Osteoporotic fractures occur most commonly, at the hip, vertebra, distal radius and proximal humerus. A combination of these is uncommon. Thirty-two women and six men treated between January 1990 and December 1999 for a combination of subcapital fracture of the humerus and hip fractures were evaluated retrospectively. The following parameters were reviewed: age, sex, pre-fall function, use of drugs, chronic and acute comorbidity, circumstances of the fall, length of hospitalization, treatment procedure, complications and post-hospitalization rehabilitation. Group I consisted of 15 patients aged 70-80 years and group II consisted of the remaining 23 patients, older than 80 years. In all 38 patients the simultaneous fractures were ipsilaterally. Hospital stay ranged from 7 to 17 days for the discharged 37 patients. Twenty-six of 28 patients, who were transferred to a rehabilitation center, returned to their previous activity of daily living (ADL). Among the nine remaining patients only five gained full recovery. A combination of fractures, occurs in the higher-age group, is quite traumatic to the patient and probably involves a greater impact force. In all patients it occurs in the ipsilateral side. In the elderly, even a minimal transmission to the osteoporotic hip can cause a fracture. The double trauma represents a better pre-morbid condition relative to patients in the same age group, thus it may serve as a prognostic indicator for success in rehabilitation.     

Entropy of dialogues creates coherent structures in e-mail traffic

We study the dynamic network of e-mail traffic and find that it develops self-organized coherent structures similar to those appearing in many nonlinear dynamic systems. Such structures are uncovered by a general information theoretic approach to dynamic networks based on the analysis of synchronization among trios of users. In the e-mail network, coherent structures arise from temporal correlations when users act in a synchronized manner. These temporally linked structures turn out to be functional, goal-oriented aggregates that must react in real time to changing objectives and challenges (e.g., committees at a university). In contrast, static structures turn out to be related to organizational units (e.g., departments).